JPS6252752B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides novel 4-(1,3-dithiolane-2
-ylidene)-2-pyrazolin-5-one derivative, its production method, and an agricultural and horticultural fungicide composition containing the derivative as an active ingredient. The 4-(1,3-dithiolan-2-ylidene)-2-pyrazolin-5-one derivative of the present invention is a new compound that has not been described in any literature, and has the following general formula: (In the formula, R ₁ is a hydrogen atom or a lower alkyl group, R ₂
represents a lower alkyl group, phenyl group or substituted phenyl group, and the substituent is a halogen, nitro group or methyl group). In the context of the present invention, 3-methyl-2-pyrazolin-5-one-4-dithiocarboxylic acid and its ethyl ester are used, for example, in Gazz.Chim.Ital. 89 526-39
(1959) and others, and such compounds have no bactericidal efficacy. However, the compound of the present invention was found to have excellent bactericidal efficacy, exhibiting excellent bactericidal activity without phytotoxicity to agricultural crops, and extremely low toxicity to mermaids and fishes. The compound represented by the general formula (1) of the present invention can be used as an agricultural and horticultural fungicide, especially for blast fungi, which is one of the main diseases of rice, and also for algal fungal pathogens that damage agricultural crops, such as Phytophthora blight of cucurbits and cucurbits. It is also effective against downy mildew and exhibits excellent medicinal efficacy. For example, foliage treatment with a chemical concentration of about 500 ppm shows a control effect against the above-mentioned pathogenic bacteria. Also, it shows a control effect against seedling damping-off fungi when mixed into the soil. The compound of the present invention has the general formula (In the formula, R ₁ is a hydrogen atom or a lower alkyl group, R ₂
represents a lower alkyl group, a phenyl group or a substituted phenyl group, and the substituent is a halogen, a nitro group or a methyl group).
It is produced by reacting 5-one-4-dithiocarboxylic acid with ethylene bromide in the presence of a base in a solvent or in the absence of a solvent. In the above, the lower alkyl group represented by R ₁ and R ₂ is an alkyl group having 1 to 8 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl,
Examples include heptyl and octyl. 2-pyrazoline-5 represented by the above general formula (2)
-one-4-dithiocarboxylic acid is prepared by a known method.
- It can be easily obtained by reacting pyrazolin-5-one and carbon disulfide in the presence of a base in a solvent or in the absence of a solvent. This compound can be isolated, but from economical considerations it is not isolated but reacted with ethylene bromide to produce the 4-(1,3-diothyrane-
2-ylidene)-2-pyrazolin-5-one derivatives can be obtained. The solvents used in the production of the compounds of general formulas (1) and (2) above are:
Water, alcohols especially methanol, ethanol,
Propyl alcohols, ethers, tetrahydrofuran, dioxane, ethylene glycol ethers, dimethylformamide (DMF), etc. are used. As the base, sodium hydroxide, potassium hydroxide, sodium methylate, sodium ethylate, etc. are used. The reaction temperature is about 0~
Although it is possible to carry out the reaction at 100°C, a temperature of room temperature to 50°C is preferable from the viewpoint of economy and reaction. Representative examples of the compounds thus obtained are as follows. Γ 3-methyl-4-(1,3-dithiolane-2
-ylidene)-2-pyrazolin-5-one Γ 1,3-dimethyl-4-(1,3-dithiolane-2-ylidene)-2-pyrazolin-5-one Γ 3-phenyl-4-(1,3 -dithiolane-
2-ylidene)-2-pyrazolin-5-one Γ 3-(2,4-dichlorophenyl)-4-
(1,3-dithiolan-2-ylidene)-2-pyrazolin-5-one Γ 3-(3-methylphenyl)-4-(1,3-
dithiolan-2-ylidene)-2-pyrazolin-5-one Γ 1-ethyl-3-methyl-4-(1,3-dithiolan-2-ylidene)-2-pyrazoline-
5-one Γ 1-propyl-3-methyl-4-(1,3-
dithiolane-2-ylidene)-2-pyrazolin-5-one Γ 3-propyl-4-(1,3-dithiolane-
2-ylidene)-2-pyrazolin-5-one Γ 1-methyl-3-propyl-4-(1,3-
dithiolan-2-ylidene)-2-pyrazolin-5-one Γ 3-(4-nitrophenyl)-4-(1,3-
dithiolane-2-ylidene)-2-pyrazolin-5-one Γ 3-butyl-4-(1,3-dithiolane-2
-ylidene)-2-pyrazolin-5-one Γ 1-isopropyl-3-methyl-4-(1,
3-dithiolan-2-ylidene)-2-pyrazolin-5-one Γ 1-t-butyl-3-methyl-4-(1,3
-dithiolane-2-ylidene)-2-pyrazolin-5-one To use the compound represented by the general formula (1) of the present invention as a fungicide, the compound may be used as it is, but in general, it is usually used as a pesticide. It is mixed with the diluent used and used in the form of wettable powders, emulsions, powders, atomizers, etc. At this time, in order to improve the effectiveness,
Auxiliary agents, such as fillers such as kaolin, bentonite, talc, diatomaceous earth, emulsifiers such as sodium dodecylbenzenesulfonate, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, fixing agents such as calcium stearate, lignin sulfone Dispersants such as acid salts, antistatic agents such as isopropyl phosphate, and other spreading agents may also be added. When the agricultural and horticultural fungicide composition of the present invention thus obtained is used, if the formulation is in the form of a wettable powder or emulsion, it is diluted with water or other solvent.
The concentration of the active ingredient is adjusted to a predetermined concentration, and in the case of powders and granules, it is diluted with a solid diluent or sprayed as is. The dilution rate and usage amount of the fungicide composition of the present invention vary depending on the type of target pathogen, the type and growth condition of the target crop, the shape of the spraying tool, the area to be applied, etc., and are selected as appropriate. The present invention will be explained below with reference to Examples. Example 1 13.2 g (0.24 mol) of KOH was dissolved in 50 ml of methanol, and 3-methyl-2-pyrazoline-5
Add 9.8 g (0.1 mole) of -one and dissolve under reflux for 15 minutes. After cooling, 11.4 g (0.15 mol) of carbon disulfide
Add and leave at room temperature overnight. Further, 18.7 g (0.1 mol) of ethylene bromide was added to this reaction solution, and when it was left at room temperature overnight, crystals precipitated. After filtering the crystals, they were washed with water and recrystallized from DMF to give 16.8 g (yield 84%) of 3-methyl-4-(1,3
-dithiolan-2-ylidene)-2-pyrazolin-5-one is obtained. mp285-286℃ Elemental analysis value C H N Calculated value (%) 41.98 4.03 13.99 Actual value (%) 41.73 4.01 14.01 Example 2 13.2 g (0.24 mol) of KOH was dissolved in 50 ml of methanol, and 1,3- 11.2 g (0.1 mol) of dimethyl-2-pyrazolin-5-one was added, and after cooling, 11.4 g (0.15 mol) of carbon disulfide was added and left overnight. In addition to this reaction solution, 18.7 g of ethylene bromide
(0.1 mol) and left to stand, crystals will precipitate.
After filtering out the crystals, the mother liquor is concentrated and water is added to the residue for crystallization. The crystals were recrystallized from ethyl acetate,
18.7 g (yield 87.4%) of yellow crystals of 1,3-dimethyl-4-(1,3-dithiolan-2-ylidene)-2-pyrazolin-5-one are obtained. m.
p.168-170℃ Elemental analysis value C H N Calculated value (%) 44.83 4.70 13.07 Actual value (%) 44.87 4.63 13.16 Examples 3-12 R ₁ and R ₂ of general formula (2) are as shown in Table 1 below. The compound of the present invention is obtained by operating in the same manner as in Examples 1 and 2, except for using the same starting materials. The melting points of the obtained compounds are also shown in Table 1.

[Table] Example 13 A composition consisting of the following components is ground and mixed to obtain a wettable powder. Ingredients Part by weight 3-Methyl-4-(1,3-dithiolane-2-
Ylidene)-2-pyrazolin-5-one 20 Kaolin 50 Diatomaceous earth 25 Sodium dodecylbenzenesulfonate 4 Lignosulfonate 1 100 Examples 14 to 24 3-Methyl used as an active ingredient in Example 13 above -4-(1,3-dithiolane-2
-Ylidene)-2-pyrazolin-5-one was replaced with the compounds obtained in Examples 2 to 12, but the same procedure as in Example 13 was repeated to obtain each hydrating agent. The following pathogen control test was conducted on some of the wettable powders obtained in Examples 13 to 24 above. Test example 1 Preventive effect test against rice blast disease (Piricularia oryzae) (pot test) Rice seedlings grown in a greenhouse (quality Echigo early, leaf age 3) were tested so that the active ingredient concentration of the hydrating powder was 1000, 500, and 250 ppm, respectively. dilute each diluted solution with water.
Spray evenly at a rate of 10ml/pot (10 pots in each area).
24 hours after spraying, a suspension of rice blast fungus spores cultured on Misato medium was spray inoculated and placed in a humid room at 25℃ for 72 hours.
Keep time. Then move it to a glass chamber. After 5 days, the number of lesions per leaf was investigated and the preventive value was calculated, and the results are shown in Table 2 below. In addition, in Table 2 below,
For comparison, the results of tests conducted in the same manner as above using the conventionally used Fuji One are also listed. Preventive value (%) = (1 - number of lesions per leaf in treated area / number of lesions per leaf in untreated area x 100

[Table] Test Example 2 Preventive effect test against gray blight (Phytophthora capsici) of cucumber (pot test).
In 2.5), the active ingredient concentration of the hydrating agent is 1000,
Dilute with water to 500 and 250 ppm, and uniformly spray each diluted solution at a rate of 20 ml per 5 pots (10 pots in each area). 24 hours after spraying, inoculate with a suspension of zoospores of Phytophthora blight and keep in a humid room at 28°C for 48 hours. Then move it to a glass chamber. Measure the severity of disease after 5 days. The results are shown in Table 3 below. For comparison, Table 3 below also shows the results of a test conducted in the same manner as above using a conventionally used captan agent. However, the above-mentioned disease severity was measured according to the following judgment. The disease severity of the cucumbers in each pot was determined as follows: 0: Healthy 1: Slight lesions observed 2: Lesions clearly observed but relatively few 3: Moderate disease severity 4: Many lesions, and on the stems and leaves Deformation is observed 5: Visually judge the condition in 6 stages of lodging or near lodging, and calculate the average severity of disease and preventive value using the following formula for 10 pots. Average severity = 0×N ₀ +1×N ₁ ...+5×N ₅ /N ₀
+N ₁ ...... +N ₅ (In the above formula, N ₀ , N ₁ ...N ₅ indicate the number of pots whose disease severity has a judgment value of 0, 1 ... 5, respectively) Preventive value (%) = (1 - treatment Area average disease severity/non-treated area average disease severity) x 100

[Table] Example 25 A composition consisting of the following components is mixed to obtain an emulsion. Ingredients Part by weight 1,3-dimethyl-4-(1,3-dithiolan-2-ylidene)-2-pyrazolin-5-one
20 Dioxane 65 Polyoxyethylene nonyl phenyl ether 5 Sodium dodecylbenzenesulfonate 10 100 The same pathogen control test as above was conducted using the above emulsion, and the same results as in Example 14 were obtained. Example 26 A composition consisting of the following components is mixed to obtain a wettable powder. Ingredients Part by weight 1-isopropyl-3-methyl-4-(1,3
-dithiolane-2-ylidene)-2-pyrazolin-5-one 20 Sodium dodecylbenzenesulfonate 3 Polyoxyethylene lauryl ether 2 Kaolin 50 Diatomaceous earth 25 100 Pathogen control test similar to the above using the above hydrating powder The same results as in Example 17 were obtained. Example 27 A powder is obtained by mixing a composition consisting of the following ingredients. Ingredients Part by weight 3-phenyl-4-(1,3-dithiolane-2
-ylidene)-2-pyrazolin-5-one 2 Talc 50 Kaolin 46.5 Isopropyl phosphate 0.5 Calcium stearate 1 100 When the same pathogen control test as above was conducted using the above powder, the same results as in Example 21 were obtained. Obtained.

Claims (1)

[Claims] 1. General formula (In the formula, R ₁ is a hydrogen atom or a lower alkyl group, R ₂
4-(1,3-dithiolan-2-ylidene)-2-pyrazoline-5, represented by 4-(1,3-dithiolan-2-ylidene)-2-pyrazoline-5
-one derivative. 2 General formula (In the formula, R ₁ is a hydrogen atom or a lower alkyl group, R ₂
represents a lower alkyl group, a phenyl group or a substituted phenyl group, and the substituent is a halogen, a nitro group or a methyl group).
General formula characterized by reacting 5-one-4-dithiocarboxylic acid with ethylene bromide in the presence of a base 4-(1,3-dithiolane-2-ylidene)-2- (in the formula, R ₁ and R ₂ are the same as above)
Method for producing pyrazolin-5-one derivative. 3 General formula (In the formula, R ₁ is a hydrogen atom or a lower alkyl group, R ₂
4-(1,3-dithiolan-2-ylidene)-2-pyrazoline-5, represented by 4-(1,3-dithiolan-2-ylidene)-2-pyrazoline-5
An agricultural and horticultural fungicide composition containing a -one derivative as an active ingredient.